Mercury biogeochemical cycling in a stratified estuary

Journal Article · Wed Sep 01 00:00:00 EDT 1993 · Limnology and Oceanography; (United States)

DOI:https://doi.org/10.4319/lo.1993.38.6.1227· OSTI ID:5297780

Mason, R P; Fitzgerald, W F ^[1]; Hurley, J ^[2]; Hanson, Jr, A K; Donaghay, P L; Sieburth, J M ^[3]

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1. Univ. of Connecticut, Groton, CT (United States)
2. Wisconsin DNR, Fitchburg, WI (United States)
3. Univ. of Rhode Island, Narragansett, RI (United States)

Total Hg in the permanently stratified Pettaquamscutt estuary was <25 pM throughout the water column, even in highly sulfidic bottom waters. Particulate Hg was typically >40% of the total Hg. Reactive Hg (Hg[sub R]) was generally <3 pM and decreased with depth, but there is Hg[sub R] even in the anoxic bottom waters. Elemental Hg (Hg[sup 0]) was highest in the mixed layer and below the detection limit at depth. Demethylation is not an important source of Hg[sup 0] in this estuary. Dimethylmercury was not detected. Monomethylmercury (MMHg) was near the detection limit in the mixed layer and increased rapidly in the low oxygen region. Dissolved MMHg correlated with bacteriochlorophyll pigments, suggesting that the microbial community plays an important role in MMHg production in the estuary. The overall distributions of dissolved and particulate Hg species result from the interaction with Fe and Mn redox cycling, particulate scavenging and sinking, and MMHg production in the pycnocline. The estimated rate of MMHg production from Hg[sub R] in the pycnocline region is 1.7% d[sup [minus]1]. Hg[sup 0] and MMHg are formed principally in the mixed layer and in the pycnocline region, respectively. Particulate scavenging is important, and sedimentation, methylation, and Hg[sup 0] production are the principal sinks for Hg[sub R].

• OSTI ID: 5297780
• Journal Information: Limnology and Oceanography; (United States), Vol. 38:6; ISSN 0024-3590
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ESTUARIES
STRATIFICATION
MERCURY
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL TRANSPORT
BACTERIA
METHYLMERCURY
SINKS
ELEMENTS
MASS TRANSFER
METALS
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
SURFACE WATERS
540220* - Environment
Terrestrial- Chemicals Monitoring &amp; Transport- (1990-)
540320 - Environment
Aquatic- Chemicals Monitoring &amp; Transport- (1990-)